There is NVIDIA Ansel. Many mods also allow free camera. Don't know if there is anything else than Ansel that will allow you to freeze time.
Life bar should disappear when when your health if full and there is no combat. Also there are mods that for example make minimap visible only in witcher senses (Friendly HUD for example). Same for all indications for potions, food, buffs and debuffs, you can make them appear only while in combat, otherwise in radial menu only (Buffs in radial menu mod). Also game has HUD toggle, by default Home key. You can also disable selected parts of HUD. There are mods that allow to scale, move and set opacity for hud elements, also to choose minimap zoom.
There isn't really anything to complain about in this regard, compared to 99,999999% games that don't even have any hud options outside of disabling some parts of it, not to even mention photo mode, this is a dream.